处理错误

PostgreSQL 中的事务与错误处理

Jason Myers

Principal Engineer

难免出错

误把饼干（Biscuits）更新了

UPDATE cookies SET quantity = 13 WHERE name = 'Biscuits';

更正为更新意式脆饼（Biscotti）

UPDATE cookies SET quantity = 1 WHERE name = 'Biscuits';

UPDATE cookies SET quantity = 13 WHERE name = 'Biscotti';

回滚错误

BEGIN TRANSACTION

UPDATE cookies SET quantity = 13 WHERE name = 'Biscuits';

ROLLBACK;

SELECT quantity FROM cookies where name = 'Biscuits';

回滚多条语句

BEGIN TRANSACTION;

UPDATE cookies SET deliciousness = 111 where name = 'Cats Tongue';

UPDATE cookies SET deliciousness = 8 where name = 'Gingerbread';

ROLLBACK;

SELECT name, deliciousness FROM cookies where name in ('Cats Tongue', 'Gingerbread');

'Cats Tongue'  10
'Gingerbread'   9

让我们来练习吧！

PostgreSQL 中的事务与错误处理